This invention relates to a unique direct injection liquid propellant gun system and, more particularly, to such a system which is adapted for use as a rapid fire, small caliber, high muzzle velocity aircraft cannon system.
The advantages of a liquid propellant gun over a conventional powder gun are numerous. Immediately, a cartridge case becomes unnecessary and can be removed. This per se is an asset, for by removing the cartridge case the cost of each round is reduced; the weight of each round is reduced; the volume of each round is reduced; the necessity for a spent cartridge ejection mechanism is eliminated; and, the projectile loading and handling mechanisms can be made more rugged and also can be made to operate faster. Additionally, liquid propellants are generally more dense and more energetic than conventional powder propellants; thus, there can be a savings in the total volume of propellant required to propel a projectile. Also, with a liquid propellant, relatively low flame temperatures can be obtained without a loss in impetus. Further, for a given projectile load, there is a savings both in weight and in volume in a liquid propellant gun and in the system of which it is a part.
The relative merits of a direct injection liquid propellant gun, as compared to a bulk-loaded liquid propellant gun, are more subtle. Direct injection capability allows the use of hypergolic propellant formulation, which increases the reliability of the gun, since the need for an igniter and an ignition subsystem is eliminated. The danger of a misfire or of a hang fire is negligible, since the introduction of both reactive products guarantees ignition. A direct injection system has no cook-off problem, since the propellant vaporizes and burns as it is injected. Research into bulk-loaded guns indicates that bulk loading is apt to cause burning instabilities and possible catastrophic detonation, unless extreme care is taken in the loading method. This type of instability problem does not exist in a direct injection liquid propellant gun. Mechanically, a direct injection gun can achieve a higher rate of fire than a bulk-loaded gun, since the extra step of loading the propellant behind the projectile before ignition is removed.
It is, therefore, readily apparent that a direct injection liquid propellant gun system is very desirable and, in fact, would constitute a significant advance in the state-of-the-art.
We have invented such a direct injection liquid propellant gun system, which said system will be disclosed and taught hereinafter.